What does the Accessory Gearbox provide?

• A. The forward supporting structure of the engine and provides the drive gears for the starter/generator, N1 Fuel control/pump and oil pump.
• B. The aft supporting structure of the engine, reduces RPM from the power turbine, and transfers power forward to the transmission Shaft.
• C. Transmits the Power of the turbine to the main transmission.
• D. It directs fuel to the main combustion chamber.

Answer: (A)

The main idea is that the accessory gearbox is the drive hub for engine accessories. It sits on the side of the engine and is driven by the engine’s rotating shaft, usually the high-pressure spool. Inside, a gear train steps down the engine speed to a usable level and powers several essential components: the starter or starter/generator, the N1 fuel control and pump, and the oil pump. This arrangement lets these systems operate directly from the engine’s motion, even when the main power path is not yet generating thrust. The other listed roles aren’t handled by the accessory gearbox: providing the aft supporting structure and transferring power to the main transmission belong to other parts of the engine and propulsion train, and directing fuel to the main combustion chamber is a function of the fuel control system rather than the gearbox.